Creping corrugated papers



Jan. 17, 1950 w. w. fiowa 2,494,723

CREPING CORRUGATED PAPER Filed Feb. 8, 1947 INVENTOR. lifl; MM 0991.1.4c: lF'awE.

F 005. BY

ATTOR EYS.

Patented Jan. 17, 1950 CREPING CORRUGATED PAPERS William Wallace Rowe,Cincinnati, Ohio, ascignor to Cincinnati Industries, Inc., Lockland,Ohio,

a corporation of Ohio Original application February 19, 1940, Serial No.319,641. Divided and this application February 8, 1947, Serial No.727,482

8 Claims. (CL 154-33-05) This application is a division of my copendingapplication Serial No. 319,641, filed February 19, 1940, now Patent No.2,425,207, which in turn is a continuation in part of the applicationwhich matured into Patent 2,190,680.

Fundamentally my invention relates to the corrugating and creping ofpapers or other webs, and finds its most important, though not exclusiveapplication, in the formation in webs of corrugations which are parallelto the longitudinal axis of the web and which may be formed in acontinuous manner, together with the creping of such webs while incorrugated conditions.

My invention relates to a novel step or series of process steps whichhave importance in a plurality of different fields, among which may bementioned, but without limitation, the corrugating and creping of websas a part of a substantially unitary operation, the creplng ofpreviously corrugated webs, and the production of special types ofcreped papers.

In this case I describe and claim the process and apparatus for formingproducts in which the widthwise gathering produced by corrugating is ingreater or less degree transformed into sinuosities of the crepingcrinkles.

The fundamental and ancillary objects of my invention will be set forthhereinafter, or will 7 be entirely clear to the skilled worker in theart on reading these specifications. For clarity in the disclosure,which is to follow, reference is now made to the drawings, wherein:

Figure 1 is a semi-diagrammatic perspective view of one form ofcorrugating mechanism in connection with which my invention may becarried on.

Figure 2 is a sectional view of a portion of one type of corrugatingsurface showing one method of binding the web to that surface.

Figure 3 is a semi-diagrammatic elevation of means for corrugating andthereafter creping a web in which the corrugated character of the web ispartially or wholly converted into a wavy conformation of the crepingcrinkles.

Figure 4 is a partial perspective view of. a doctor usable with themechanism of Figure 3.

Figure 5 is a partial perspective view of another doctor usable with themechanism of Figure 3.

Figure 6 is a plan vew of a creped web in which corrugations have beenconverted into a wavy configuration of the crinkles.

I shall first describe the corrugating portion of my apparatus. In theproduction ofi longitudinally corrugated sheets, by continuous proc- 2cases, as set forth in the patent of Rowe and Morris No. He. 20,970,dated January 3, 1939, the web is actually taken up or gatheredtransversely. It is therefore not possible to contact the websimultaneously across its width with gathering elements whichinterdigitate simultaneously and completely to produce the desiredgathering. If this were done, the web would bind andsplit. As aconsequence it is the usual practice to begin to gather the web at onepoint (usually, though not necessarily, in the center of it) and then asthe web moves, progressively form additional lateral gatherings untilultimately the whole web is gathered transversely. Ordinarily a centrallongitudinal corrugation is formed first and after this has been formed,another corrugation is formed on each side of it, the additionalcorrugations being formed in pairs until the operation is completed forany given length of the web. If it is assumed that corrugating is beingdone by presenting to the web upon one side, means providing acorrugated surface, and by presenting to it on the other side, meanswhich successively and progressively depress the paper between the landsor ridges of the first mentioned corrugating means it will be found in"actual practice that there are forces tending to cause previously formedcorrugations to come out or be lost during the progress of the web. Oneof these forces is the natural resilience of the web which causes it totend to become flattened out after it has been corrugated. Another ofthese forces is the actual pull on a previously formed corrugation,caused by the depressing of laterally disposed portions of the web toform additional corrugations. As a consequence, it has been found inactual practice, given corrugating means upon one side of the web anddepressing means on the other which act successively to formcorrugations by interdigi tation, some means must also be provided forholding previously formed corrugations as such, at least until theformation of laterally adjacent ones. This presents a substantialmechanical problem, which problem has been solved mechanically by theteachings of said Rowe and Morris, to which reference has been made.

Essentially in the practice of my invention, I accomplish this purposeby binding the paper to a corrugating means, at least at the time of theformation of any given corrugation in a way which will be positive.

As an exemplary machine and procedure, I have illustrated in Figure l, acylinder l, which is grooved on its peripheral surface. A suitable seaves web 2 is led to the surface of this cylinder in any suitable way,and in order to term corrugations therein, the paper is successivelydepressed into the grooves of the cylinder by a series of progrcssivclyacting elements starting with a center roller or sheave 3, followed bylaterally adjacent ones 6 and 5, and additional pairs of laterallyadjacent ones ii and l, etc. This arrangement alone would not becommercially successful for the manufacture of corrugated paper withoutthe provision of holding means as aforesaid. This holding means Iprovide by adhesively binding the paper to the cylinderas the corrugations are formed therein, the adhesive being sui iicient to maintain thecorrugations while others are being formed.

By this I mean that the adhesive must be of such character or so used asnot to interfere with the widthwise contraction of the sheet duringcorrugating but must eiiectively act as hold= ing means after thecorrugations have been formed. Thus an adhesive may be employed which isrendered tacky only after the corruga tions have been formed, ashereinafter set forth. Or an adhesive may be employed which is soft andslippery enough to permit side slip of the web during corrugating, butwhich, once the web has been pressed down into a groove will unitestrongly resist the direct lifting action en countered when adjacentcorrugations are being produced. The adhesive may be applied either tothe web or to the cylinder or to both, by any suitable means.

I may coat either the entire surface or" the cylinder or the entiresurface of the paper or both with adhesive, prior to the corrugating oithe paper. it is also possible to employ an adhesive substance which isnormally non-adhesive or which has been caused to assume a non-adhesivestate, and then to develop adhesiveness therein as and when desired,via, upon the corrugating of the paper. Asphalt or other bituminous sub=stances, though not the only adhesives which I may employ, are highlyadvantageous for certain types of work. Eitumens may be chosen which aresubstantially hon-adhesive at ordinary temperatures, but which may becaused to become adhesive upon the application of heat; and heat may beapplied either by external means, by con trolling the temperature of thecorrugatlng member E, or by heating the depressing means 3, t, b, etc.This is also true of other thermoplastic substances, including butwithout limitation, incompletely polymerized synthetic resins.

One procedure suitable for permitting the corrugating oi the web whilebinding the paper web to the cylinder substantially throughout the areaof the web so as to permit over-all 'creping, is to coat the web with athermoplastic substance tempered to a non-adhesive condition, employ anunheated or even cooled cylinder, and develop adhesiveness by the use ofheated deforming elements, followed by a heated, grooved roll orequivalent device just ahead oi the creplng line, or line of engagementof the doctor with the web.

My process and mechanism is adaptable to the corrugating of papers whichhave not previously been creped, as has been seen. If plain paper isbeing operated upon, it may be creped transversely at the time of theremoval of such paper from the corrugating means. I am aware that it hashitherto been suggested to lead paper on to a corrugated cylinder andremove it therefrom by a serrated knife so as simultaneously to crepeand wave the pope flhis however, has not proved to be practicable, andso far as I know there has hitherto been no commercially successfuloperation of this kind. While it is true that no successful way has beenfound to bind the paper to the corrugated cylinder, and that moisturealone cannot be depended upon, while the use of vacuum or air blasts haslikewise not been a success, and while a positive adhesive union of thepaper and the corrugated cylinder or the like solves this aspect of thedimculty, yet the failure of the prior art to crepe successfully from agrooved cylinder has in my opinion been due to a lack of understandingof the principles which I shall now set forth.

(Consider the situation shown in Figure 2, a corrugated cylinder to,with a paper web We cemerited solidly to the surface thereof, over itsentire area, by the cementing medium 9 la, which may in this case be anasphalt or the like, but may also comprise a number of other adhesives,such as latex, rubber -resin combinations, incompletely polymerizedsynthetic resins, etc. It is possible merely to scrape the web from thecylinder with a sharp knife, is to say a knife or doctor contacting thecylinder and having so large a meeting angle of its surface with thesurface of the cylinder to exert only a lifting action upon the web.This feasible it the knife is so disposed as not to web by lifting partsof the web from the ridges or lands of the cylinder before closely partsare lifted iroin the bottoms of the grooves.

But if the cm is to crepe the web as it is removed from as groovedcylinder, whereby the web will have longitudinal stretchability imto it,the first desideraturr. is the use of a o or doctor which a meetingangle of its sol race with the surface of t e cylinder so small to crowdpaper upon itself to form creping crinlzles it, that is to say, in orderto crepe one must employ a doctor which will provide a proper *crepingangle or creping V. For commercially desirable amounts of iongitudirialstretchabillty a creping V of no large than 90 is desirable; and theamount of stretchability will be influenced by the creping angle or V.

In melting a product stretchable bothv widthwise and lengthwise, wherethe product is creped as it is removed from a corrugated surface, if thecrinkles are formed in such a way as to tend to take up the sheetwidthwise, they can only do this to the extent that they flatten thecorrugations. Thus there are two extreme operations, the production of acrinkled web in which the lateral stretchabllity arises fromcorrugations, and the production of a crinkled web in which the lateralstretchabllity has been absorbed in a configuration of the crinkles, andthe corrugations as such have disappeared. between which there is arange of intermediate results. To the extent that the transversestretchability inherent in the corrugations is transferred to thecrinkles, the crlnkles (when the web is viewed in planl assume thezigzag or herringbone conformation shown at 24 in Figure 6.

Efforts to form such a product (either fully herring-boned and fiat, orpartly herrlngboned and partly corrugated) involve the formation ofcrinkles in the web which for the most part lie aslant to the major axisof the web when the web is viewed in plan. While the possibility of theformation of such products has hitherto been suggested, the commercialfailure of the art has been due to a laclrof understanding of thefactors involved and the mode and mechanism for the successful formationof such herringbone or zigzag crinkles. It is clear enough that theirformation involved a creping means which will remove the web from thevalleys of the corrugated cylinder before its removal from the ridges.But the crinkles must be formed in such a way as to translate the wavytransverse section of the web into more nearly a flat plane; provisionmust be made for the removal of the web from the grooved cylinder in amore or less flattened condition; and sumcient longitudinalstretchabillty must be provided to make the product interestingcommercially.

Taking the last of these considerations first, a creping V of therequired small angularity must be provided if sufficient stretchabilityin any direction is to be derived from the crinkles; but the art has nothitherto understood how to provide such a creping V in a doctorproducing zigzag crinkles and having the other characteristics foroperability. Further, it will be apparent that where the crinkles aredisposed at an oblique angle to the major axis of the web, a portion ofthe 'stretchability resident in the crinkles is derivable transverselyof the web, and a portion longitudinally. This is why it is possible toproduce from a corrugated sheet a substantially flat sheet where thetransversegathering produced by corrugating has been translated into thetransverse stretchability resident in the oblique crinkles. Thestretchability in any given direction is a function not alone of thelinear gathering of the web in a direcltion perpendicuar to thedirection of the crinkles but also of the angular relationship of thecrinkles to the direction of stretch. It follows from this that if a webhas been gathered widthwise a certain amount by corrugating, and if thisweb is transformed into a flat herringboned web in which the lateralgathering is now wholly resident in crinkles having a certain angularrelationship to the major axis, there is theoretically only onelongitudinal stretchability possible under these circumstances. Fromthis, again, it follows that in a flatherringbone sheet where thewidthwise gathering is predetermined, if the longitudinal stretchabilityis to be varied, the angle of the crinkles to the major axis must bevaried.

To form a herringboned sheet, therefore, the linear gatheringperpendicular to the direction of the crinkles must be produced withreferences to the angularity of the crinkles to the major axis of theweb. Another way of stating this is, having provided a creping V capableof producing a given linear gathering perpendicular to the crinkles, theknife must be configured to remove the web from the valleys of thecorrugated creping surface sufficiently ahead of the points where theweb is removed from the lands or ridges to give the needed angularity ofthe crinkles. With these factors in mind, however, it is possible toconfigure a knife and provide a creping V which with a given widthwisegathering will provide a desired lonitudinal stretchability. Of course,in designing a knife, other factors affecting the action of the knifemust be taken into account, such as the weight and other characteristicsof the web, and the weight and consistency of the coating thereon. Someleeway is possible. If the widthwise gathering taken up by the crinklingoperation is not equal to the gathering due to the corruating, theresultant creped web will not be flat. If the creping tends totake theweb up widthwise more than the gathering due to corrugating, the webwill lose the excess stretchability by the stretching of the crinklesimmeditaeiy after they are formed, (with a concomitant change inangularity of crinkles) if the web is strong enough to stand the strainand if the disparity is not too great.

There remains the problem of removing the web. Under the circumstancesoutlined the web will be removed from the creping line in a directionoblique to theutangent, and must, be so removed. Theoretically there isbut one correct angle of removal for any given set of the conditionsdiscussed above. Actually there is an appreciable latitude.Nevertheless, the knife must be devoid of configurations which wouldinterfere with the movement of the web in substantially the correctplane of removal.

In Figure 3 I have shown the web corrugated by being made to conform tothe grooved surface of the cylinder I. The web is removed from thecylinder by a doctor 24 disposed generally neither tangentially norradially, but at an obtuse angle to the tangent. shown as being removedneither in a tangential nor a radial direction but along an intermediateplane. In Figure 4 I have shown the knife N .in greater detail. Theunder side of the knife has been grooved to permit it to conform withthe grooving of the cylinder at the angle at which the knife isdisposed. The leading edge: of the knife has been beveled as at 21 alongsuch a plane as to permit removal of the web in the direction shown at25. The portion of the knife which forms the creping V is indicated at28. Taking into account the bevel 21 and the V portion 28, together withthe general angularity of the knife to the tangent, the knife has beenso configured as to remove the web from the valleys of the cylinder farenough in advance of the points of removal of the web from the lands orridges, to give the required general angularity to the crinkles.

In Figure 5, I have shown a corrugated knife 29, cut away to permit itsapplication to the cylinder at an angle to the tangent. The creping V isshown at 30. The corrugated knife, being of uniform thickness where itcontacts the cylinder does not require beveling. I prefer when formingthe creping v portion of any of these knives to take into account thediffering angularities of different portions of the ridges and valleysof the cylinder, and grind the V portion of the knife to give a crepingV of constant angularity throughout.

My process is applicable to webs in general including but withoutlimitation webs of paper or other felted fibrous material, cloth andtextiles, and amorphous films-such as the regenerated cellulosicmaterials, the rubber hydrochlorides, and to thin sheet materialsgenerally such as backed or unbacked metail foils.

Modifications of my invention may be made without departing from thespirit thereof, and I do not desire my invention to be limited otherwisethan as stated in the appended claims, wherein I have endeavored to setforth what I believe to be the essential novelty of my invention.

I claim:

1. Apparatus for producing a multi-lateraily' stretchable web whichcomprises a grooved cylinder, means for causing the web to conform tothe surface of the cylinder whereby the web is contracted widthwise, andwhereby the web may be caused to adhere to the surface of the cylinderwith the interposition of an adhesive therebetween, and creping meansfor removing the The herringboned web 25 isweb from the surface of thecylinder in corrugated and creped condition, said means comprising adoctor having a portion forming with the surface of the cylinder 9.creping V along a sinuous line across the face of the cylinder, theangle of the creping V throughout said line being not greater thansubstantially 9W, said doctor further having its portions which liewithin the grooves of said cylinder exteding beyond the radial planewhich includes the points of contact of said doctor with the landsbetween said grooves whereby as to remove the web from the valleys ofsaid cylinder in advance of its removal from the peaks thereof.

2. Apparatus for producing multi-laterally stretchable webs comprising agrooved cylinder, means for causing a web to conform to the sur-- faceof said cylinder whereby the web is taken up widthwise and corrugatedand whereby the :web may be caused to adhere to the surface of thecylinder with the interposition of an adhesive therebetween, and meansfor removing the web from the surface of the cylinder in crepcd formunder condition where a portion of the widthwise gathering istransferred to the crinkles, said means comprisin a doctor presenting acreping V of not substantially greater than 90 to the tangent of thecylinder and having its portions which lie within the grooves oi saidcylinder extending beyond the radial plane which includes the points ofcontact of said doctor with the lands between said grooves whereby toremove the web from the valleys of the corrugations in the cylinder inadvance of the removal thereof from the crests of the corrugations andhaving a creping angle proper for the production of a givenstretchabilit under given creping conditions, said doctor having all itsportions lying below a plane, at an angle to the tangent, suitable tothe degree of widthwise gathering taken up in the formation 01 thecrinkles by said doctor, whereby to permit removal of said web from saidcylinder substantially in said plane.

Apparatus for producing multi-laterally stretchable webs comprising agrooved cylinder, means for causing a web to conform to the surface ofsaid cylinder whereby the web is taken up widthwise and corrugated, andwhereby the web may be caused to adhere to the surface of the cylinderwith interposition of an adhesive therebetween, and means for removingthe web from the surface of the cylinder in creped form under conditionswhere a portion of the widthwise gathering is transferred to thecrinkles, said means comprisin a doctor shaped to remove the web fromthe valleys of the corrugations in the cylinder in advance of theremoval thereof from the crests oi the corrugations and having a crepingangle proper for the production of a given stretchability under givencreping conditions, said doctor being cut away as to permit removal" ofsaid web from said cylinder in a direction, at an angle to the tangent,suitable to the degree of widthwise gathering taken up in the formationof the crinkles by said doctor, said doctor-comprising a body of metalangularly disposed to said tangent, grooved beneath so that the leadingportions of said doctor will conform to the corrugations of saidcylinder, shaped along the line of conformation with a sinuous surfaceto provide the said creping angle, and shaped slopingly back from thecreping angle portion to provide for the angular removal of said web.

4. Apparatus for producing multi-laterally means for. causing a web toconform to the surface of said cylinder whereby the web is taken upwidthwise and corrugated and whereby the web may be caused to adhere tothe surface of the cylinder with the interposition of an adhesivetherebetween, and means for removing the web from the surface of thecylinder in creped form under conditions where a portion of thewidthwise gathering is transferred to the crinkles, said meanscomprising a doctor shaped to remove the web from the valleys of thecorrugations in the cylinder in advance of the removal thereof from thecrests of the corrugations and having a creping angle proper for theproduction of a given stretchability under given creplng conditions,said doctor being cut away as to permit removal of said web from saidcylinder in a direction, at an angle to the tangent, suitable to thedegree of widthwise gathering taken up in the formation of the crinklesby said doctor, said doctor comprisin a body of metal of substantiallyuniform thickness shaped to conform to the surface of said cylinder, theleading portion of said body being cut away at an angle and the edge ofsaid portion so shaped asto provide a creping angle.

5. A process of producing multi-laterally stretchable webs whichcomprises causing said webs to conform to the surface of a groovedcylinder. adhering said webs to said cylinder with the interposition ofan adhesive therebetween, and removing said webs from said cylinder by adoctor shaped to remove the web first from the valleys of thecorrugations in said cylinder and afterwards from the crests thereof,said doctor being shaped to provide a creping angle, of not greater thansubstantially throughout the line of contact with said surface andconducting the web away from said doctor at an angle to the tangent ofsaid cylinder proportioned to the degree of lateral and longitudinalstretchability of said Web so removed.

6. A process of imparting multi-lateral stretchability to a web whichcomprises causing said web to conform to a grooved surface and bindingsaid web to said surface by means of an adhesive, afterward removingsaid web from said surface first in the valleys thereof and thereafterfrom the peaks thereof by a doctor having a creping v of not more thansubstantially 90 while forming oblique crinkles in said web,proportioning the angularity of said crinkles and the amount ofstretchability produced thereby to the widthwise gathering of the web soas to produce a web which is longitudinally stretchable, and in whichthe corrugations have in part at least been taken up by the wldthwisegathering due to oblique creping crinkles.

7. A process of imparting multi-lateral stretchability to a web whichcomprises causing said web to conform to a grooved surface and bindingsaid web to said surface by means of an adhesive, afterward removingsaid web from said surface first in the valleys thereof and thereafterfrom the peaks thereof by a doctor presenting a creping V of not morethan substantially 90 throughout, while forming oblique crinkles in saidweb, proportioning the angularity of said crinkles and the amount ofstretchability produced thereby to the widthwise gathering of the web soas to produce a web which is longitudinally stretchable,

- and in which the corrugations have in part at least been taken up bythe widthwise gathering due to oblique creping crinkles, and carryingsaid web awaiy from said suriace at an angle determined by the lateraland longitudinal stretch l0 angle oi. not more than substantially 90throughout whereby suflicient stretchability is imparted to said web tocause the corrugations in said web to be transformed in substantial partat least ability to a web which comprises causing said 5 into widthwisestretchability resident in oblique web to conform to the surface. ofcorrugated means with the interposition of an adhesive substancetherebetween, removing said web from said surface by means of a doctorand shaping said doctor toproduce oblique crlnkles therein by providingsaid doctor with portions extending forwardly into the corrugations ofsaid cylinder beyond a radial plane including the points of contact ofsaid doctor with the tops of said corrugations. and further shaping theedge of said doctor contacting said cylinder, to provide a erepingportions of sinuous crinkles.

WILLIAM WALLACE ROWE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 15 2.190.680 Rowe Feb. 20, 19402,425,207 Rowe Aug. 5, 1947

